Speed control for motor driven cameras



Nov. 9, 1943. w. w; EATON 2,333,772 v SPEED CONTROL FOR MOTOR ORIVBNCAHERAS Filed June 4, 1942 FIE-1.1. FIG.4. F|G.5.

WILLIAM W EA TON INVENTOR ATT'Y & AG'T Patented Nov. 9, 1943 SPEEDCONTROL FOR MOTOR DRIVEN CAMERAS William W. Eaton, Washington, D. (3.,assignor to Eastman Kodak Company, Rochester, N. Y., a corporation ofNew Jersey Application June 4, 1942, Serial No. 445,727

3 Claims. 7 (Cl. 171-221) This invention relates to speed controls formotor driven cameras, and a principal object thereof is the provision ofmeans whereby a camera such as is used in taking moving" pictures may bedriven at different speeds, means being provided so that the operatormay select the speed required, and the camera will then run accordinglyunder the control of the usual governor. The invention contemplates acombination of a motor and a governor in such a manner that the governoris equally efiective in controlling the motor within close limits at anyselected speed. An important feature provides for automaticallyconditioning the electrical connections to the motor as each speed isselected by the operator. Other objects and advantages of the inventionwill be set forth in the specification, together with the drawingherewith, in which like reference characters indicate like partsthroughout, and in which Fig. l is a side elevation, somewhatdiagrammatic, of a motor and a governor therefor;

Fig. 2 is a diagram of the electrical connections when set up for slowspeed operation;

Fig. 3 is a similar diagram, when arranged for a higher speed; and

Figs. 4 and 5 are modified forms of the invention, partiallydiagrammatic as in Fig. 1.

In Fig. 1, a motor M, which may drive the shutter and the iilm feedmechanism of a motion picture camera (not shown), has a shaft I carryinga disc l2. A lever I3 fulcrumed at H has a brake shoe l5 at its upperend, adapted to bear against and retard the disc l2 and therefore themotor. A spool member l6 on the motor shaft II is engaged by toggle armsextending from governor weights I8, normally urged toward each other bya spring l9. The operation of the governor is the same as those incommon use in springdriven cameras, viz., an increase in speed causesthe weights l8 to fly further apart, whereupon spool I6 is moved awayfrom the motor and the disc |2 wipes against the brake shoe l5 andthereby holds the motor to a limited speed.

Near the lower end of lever I3 is a control member comprising a combinedswitch and mechanical stop, indicalkd in the drawings at 2|]. Thisswitch carries on its pivot 2| a plate 22 on which are adjustable stopscrews 23 and 24, the screw 24 extending farther from the pivot 2| thanthe screw 23. A spring 25 is arranged to bias the lever I3 in aclockwise direction so that its lower end bears positively against oneof the screws 23 or 24, whichever is in the lowermost position, therebyestablishing a definite position for the brake shoe l5 relatively to thedisc l2. In the position shown, the lever l3 rests against the screw 24,and therefore the brake shoe I5 is closer to disc l2 than when the plate22 is turned clockwise by means of the operating handle 26.

Fixed to the plate 22 or the shaft 2| thereof is an insulated crossarm21 having a contact plate 28 on one end and a similar plate 29 on itsother end. These plates are adapted, respectively, to bridge fixedcontact posts 30, 3| and 34, 35, as in Fig. 3, or 3|, 32 and 33, 34 asin Fig. 2. The position of the handle 26 is at all times consistent withthe position of arm 21, as indicated in broken lines.

In a motion picture camera or the like, driven by a motor, the latter isusually a D. C. unit adapted for battery operation. The presentinvention includes the use of a plurality of batteries for high or lowspeeds of the motor respectively, the batteries being arranged inseriesfor.

the higher speed and in parallel for the lower speed. The position ofhandle 26 determines each speed range.

Fig. 2 shows diagrammatically the wiring connections when the controlhandle 26 is moved to the low speed position, to place the batteries inparallel. Two batteries B1 and B2 are so arranged that with the arm 21in the position shown, current from E2 flows through wire 36 to post 33,thence through plate 29 to post 34 and wire 31 to junction 38. Currentfrom E1 flows through wire 39 to 38, and here the two sources combineand feed through manual switch 40 to motor M, back to B: through wireand to B1 through wire 42, post 32, plate 28, post 3| and wire 43. It isunderstood of course that the voltage is the same in both batteries. Themotor then will run at low speed and the weights It! will move outwardlya very slight amount, so that the brake shoe l5 will act on the disc l2to retard the motor as soon as the latter slightly exceeds the low-speedmaximum. Lever I3 cannot be forced out further because its lower end isbearing against the stop screw 24.

If now the handle 26 is swung to the opposite end of its movement, as inFig. 3, the electrical connections are changed accordingly, and thebatteries can only work in series with each other and the motor, asfollows: from B2 to wires 36, 44, post 30, plate 28, post 3|, wire 43,B1, wire 39, switch 40, motor M, wire 42, to B2. The batteries aretherefore in series, the motor is subjected to a higher voltage, and itsspeed increases. As the stop screw 23 now is aligned with the lower endof lever H, the disc I! may move out farther beiore contacting the brakel5. As the motor speeds up it will quickly reach a predetermined limit,the governor will move the disc I! against the brake. and the speed willbe held constant at the higher limit.

In Fig. 4 a modification is illustrated wherein a. crank 50 extendingfrom handle 26 moves a bar 5| vertically. This bar is slotted at 52 andsuitably guided, as by pins 53. In the position shown (low speed) abrake surface 54 is in position to check the disc l2, but when thehandle 26 is moved to the high-speed position the bar II is retracteddownwardly and a brake surface 55, farther out from the disc, is thenthe only part that the disc will contact.

Fig. 5 indicates a lever 63, pivoted at 64 and spring-pressed toward thedisc II. A cam 60 on shaft 2| has a concentric periphery 6| againstwhich the lever 63 bears when handle 26 is set for low speed, the brake65 then being nearer the disc l2 than when the handle 26 is moved tohigh speed position, where a portion 62 of greater radius than the rim6| forces lever 63 away from disc I! to permit the latter to move out asthe governor speeds up with the motor.

Modifications of the electrical circuits herewith illustrated may bedevised, and the combined switch and brake-adjusting device may bedifferently designed without departing from the intent of the invention,the scope of which should be considered as encompassed within thefollowing claims.

I claim:

1. In a speed control for a motor driven camera or the like, thecombination, with a motor and a plurality of batteries, of agovernor'for the motor including a brake and a brake carrier, adjustablestops adapted to engage the brake carrier electrical connections betweenthe batteries and the motor includingflxed contacts, a contact membermovable with the stops, said electrical connections being so arrangedthat in one position of the stops the contact member closes a seriescircuit through the motor and batteries, and in another position or thestops said contact member closes a circuit through the motor with thebatteries in parallel.

2. In a speed control for a motor driven camera or the like, thecombination, with a motor and a plurality of batteries, of a governorfor the motor including a brake and a brake carrier, adjustable stopsadapted to engage the brake carrier to establish a high speed or a lowspeed limit for the motor, two sets 01' fixed contacts, electricalconnections between the contacts, the batteries and the motor, and acontrol member movable with the stops to close a circuit through themotor with the batteries in series when the high-speed stop iseffective, and to close a circuit with the batteries in parallel whenthe low-speed stop is effective.

3. In a speed control for a motor-driven camera or the like, thecombination, with a motor adapted I for battery operation, of a brakeand a brake carrier, a movable control member comprising acircuit-closing member and stops adapted to engage the brake carrier toestablish high and lowspeed limits for the motor, a plurality oibatteries, and-two sets 01' fixed contacts connected with saidbatteries, said contacts being so arranged that when the. brake carrieris in high speed position the circuit-closing member completes a circuitthrough the motor with th batteries in series, and when the brakecarrier is in low-speed position said member completes a circuit throughthe motor with the batteries in parallel.

WILLIAM W. FATON.

